Bioequivalence study of two formulations of itraconazole 100 mg capsules in healthy volunteers under fed conditions: a randomized, three-period, reference-replicated, crossover study.

BACKGROUND: The aim of the study was to evaluate the bioequivalence of two itraconazole 100 mg capsule formulations. RESEARCH DESIGN AND METHODS: The single-center, open-label, randomized, three-period, three-sequence, reference-replicated, cross-over study included 38 healthy subjects under fed conditions. In each study period (separated by a 14-day washout), a single oral dose of the test (T) or reference (R) product was administered. Blood samples were collected at pre-dose and up to 72.0 h after administration. The calculated pharmacokinetic parameters, based on the plasma concentrations of itraconazole and hydroxy itraconazole, were AUC0-72h, AUC0-∝, Cmax, Tmax, T1/2 and Kel. RESULTS: The 90% CI for the test/reference geometric means ratio for the parent compound, itraconazole, was in the range from 85.29% to 116.07% for AUC0-72h. Since the coefficient of variation (CV) for the reference product was 44.95% for Cmax, the 90% CI for this parameter for itraconazole was 93.49-133.78%, which was within the proposed limits of the EMA for bioequivalence of 72.15-138.59%. During the study, 4 subjects encountered a total of 14 mild adverse events. CONCLUSIONS: The use of the reference-scaling approach with 3-period design (TRR, RTR, and RRT) was an efficient way to demonstrate that two commercially available oral itraconazole formulations met the predetermined bioequivalence criteria.